In systems for purifying and reclaiming of volatile liquids, in particular by emptying or renewal of old refrigeration systems, it is relevant to collect the volatile liquid, e.g. R-12, R-22 or R-134A, upon the liquid being brought from its gaseous phase into its liquid phase in a condenser, such that the collected liquid may be reused. In principle the condensate may be filled into the collector tank without the latter having to be vented, because the vapor or gas of the condensate in the upper tank space will maintain its gas pressure also when this space is narrowed by the progressive charging of liquid condensate into the tank. As the condensate rises in the tank the gas will diffuse or condense down into the liquid, such that the gas pressure above the liquid will remain constant when the temperature is constant. Normally, however, there will occur a certain separation of non-condensible gas, mainly of atmospheric air, and as the tank is filled this gas will give rise to an increased pressure in the tank, concurrently with a further pressure build-up due to the separation of non-condensible gas from the currently introduced condensate.
This increased pressure gives rise to some problems, for example an increase of the condensation pressure, whereby more energy is needed for the condensation of the volatile liquid, and, if the collector tank is to be utilized just reasonably effectively, that is to be widely filled for collecting reasonably large portions of the condensate, ready for delivery, then it is, in practice, imperative to carry out, from time to time, a blowing off or release of the non-condensible gas from the tank, and it is well known that this can be done based on the use of a pressure switch controlled blow-off or release valve at the top of the tank. Hereby a blowing off or release can be initiated automatically, when the pressure in the tank has risen to a predetermined maximum, and it can be interrupted when the pressure has decreased suitably, optionally controlled just by the hysteresis of the pressure switch.
However, the blowing off of the non-condensible gas gives rise to problems in that, along with the releasing or discharging of the non-condensible gases into the atmosphere, a certain amount of condensible gas will inevitably be discharged, and, as well known, from an environmental point of view, a release of considerable amounts of refrigerant gas, mainly originating from the refrigerants R-12 and R-22, have a decomposing effect on the ozone layer around the planet. Such a discharge of the condensible gas is particularly noticeable when the temperature is relatively high, because the concentration or the pressure of the condensible gas will then be relatively high in the collector tank. This circumstance is made even worse by the fact that during the opening time of the blow-off or pressure relief valve the pressure in the collector tank will be reduced such that the condensate will evaporate further, whereby towards the end of the blow-off or release period, there will occur a further increased content of the condensible gas in the blow-off or discharged product.
A possible solution to this problem resides in the mounting of a cooler element in connection with a blow-out or discharge pipe from the collector tank, such that the exhausted or discharge gas will generally be cooled to the condensation temperature of the condensible gas, whereby the critical fraction of the gas is condensed and falls back into the tank without being released to the atmosphere. However, experiments have shown that, in practice, this solution is unrealistically expensive, if it shall be reasonably effective, since during the relatively brief blow-out or release periods, a particularly intensive heat exchange with the blow-out or released gases should take place.
In response to a similar type of problem in, for example DE-B2-25,15,605, a refrigeration system is proposed having means for separation of such air, which penetrates into the refrigerant during the operation, and which is currently separated in the condenser unit of the system. This unit is provided with a built-in, integrated control device for the blow-off or release valve and consists of a bellows mounted in a discharge duct from the condenser, with the condensate therefrom flowing further downwardly into an accumulation container. The accumulation container has a lower outlet for the condensate and and upper inlet for the gas to be condensed, and, in the container, there is mounted a float serving to close the outlet when the liquid level is low, while for a high liquid level the float will close the flow of condensate from the upper condenser chamber and therewith also close the feed of hot gas to the condenser, thereby providing for security in case of operational interruptions. The bellows is partly filled with the refrigerant as used in the entire system, whereby the bellows, through a rod, seeks to press a valve head into closing engagement with an upper blow-off or release opening for the gas, while the bellows, rigidly supported at its lower side, is inversely influenced to be compressed by the gas pressure existing in the condenser chamber. Thereby the blow-off or release valve will be opened when, in the condenser chamber, there is build up a noticeable overpressure originating from the partial pressure of the non-condensible gas, while the bellows will also serve the purpose of releasing or compensating for the partial pressure of the condensible gas, for example, by the inner pressure in the bellows, whereby the temperature dependence will be eliminated.